Note 1. When you open the package and take out the product, you may find that its thickne is smaller than expected. do not worry! You can soak in water for 2-5 minutes and then blow dry to restore the normal thickne. 2. When you use spray glue/double-sided tape, please make sure the wall is flat and free of foreign matter such as powder, which will affect the effect of the paste. Specifications Size: 12x12x1 inch(30x30x2.5 cm) Material: Polyurethane Color:Black,Red,Blue,Pink Quantity:50pcs In a recording studio, the hard wall surface will give us unneceary sound reflections, and the corners of the room will give us unneceary reverberations, causing the problem of unclear sound. acoustic foam panels can solve such problems well. soundproofing foam uses a new polyurethane sound-absorbing material, which is proceed and formed through a mature foaming proce and can greatly improve the sound quality in your room. Each piece of soundproofing foam is added with flame retardant materials and paed the environmental protection test of SGS, which is a product that customers can trust. Sound Absorption Principle: acoustic foam panels is full of fine voids and semi-open holes, which can absorb the high, middle and low frequencies of the sound, attenuate the sound, and lower the interference and reverberation of the sound reflected in the room to ensure the clarity of the sound.